UPS (fittingly enough) just delivered the replacement RBC7 battery pack for my big SU3000 rack-mount UPS, which has so far been unresponsive. Swap in the RBC7 pack for the one known to be bad (it takes two of them), and ... it powers up.
However, it complains that its other battery pack is bad and needs replacement.
However, there is another known-good RBC7 battery pack in my SU1400.... a little quick swapping around, and I'll have the SU3000 online. Then I can get a new battery pack for the SU1400 when budget permits. (I will, however, need to shut down all the machines to make the swap.)
UPDATE: The swap has been made, the SU3000 is up and running, and everything on this side of the room is now running off it. Interestingly, while the SU1400 was indicating 80% or better load, the SU3000RM with the same load is indicating only about 20% load. (I won't have exact numbers until I get it hooked up to apcupsd.)
Now I get to see if I can assemble a working battery pack for the SU1400 from the two failed RBC7 packs.